Why am I not happy?? ....

I have a beautiful 2 week old boy, we had a very complicated labor which ended in an emergency c section. He spent 3 days in NICU we both spent 5 days in hospital and I now have an infection in my wound. I'm finding that I'm so teary and break down into floods of tears often early hours in the morning. I feel like I'm doing such a crap job and don't really know what to do. He now has a horrible cold the poor boy. My fiance was so good like amazing then the last few days I've struggled with him he's made comment like I'm dragging him down and then this evening at 3am I asked him to go and get some more milk from downstairs because I was feeding I thought he fell back to sleep so asked him again and he told me to shut up and got his things and is now sleeping downstairs. It's times like this I'm feeling so alone and I don't know what I'm suppose to do or if this is normal to feel this crap. I would really appreciate some advice. Thank you x